<?php
$key = "3";

switch ($key) {
    case "1":
        echo "等于了1";
        break;
    case "2":
        echo "等于了2";
        break;
    case "3":
        echo "等于了3";
        break;
    case "4":
        echo "等于了4";
        break;
    default:
        echo "啥也没匹配到";
}

